1. Field of the Invention
The present invention relates to a method and apparatus for calibrating a gyro-sensor, and more particularly, to a method and apparatus for calibrating a gyro-sensor by which a gyro-sensor can be calibrated using data which is obtained by measuring an angular velocity and a gyro output value of a moving body equipped with the gyro-sensor.
2. Description of Related Art
A gyro-sensor is one example of an inertial sensor. An inertial sensor senses the motion of a handheld terminal and may be configured with an accelerometer and a gyroscope. An accelerometer is a sensor that measures an acceleration of a moving object, while a gyroscope is a sensor that measures a rotational angular velocity of a moving object. Gyro-sensors, which provide angular displacement and angular velocity information, have been widely adopted in various fields such as model airplane attitude control, and inertial navigation system (INS) for the guided control of ships, aircrafts and munitions. In other words, the application of gyro-sensors ranges across almost all existing industrial fields such as automobiles, ships, factory automation, marine exploration, and airspace exploration. Technology has been developed in earnest and has been continuously improved according to a demand for a small-sized, lightweight, less expensive, highly-efficient and precise gyro sensors.
From the viewpoint of manufacturing cost, gyro-sensors can be classified into high-priced gyro-sensors and low-priced gyro-sensors. While ensuring excellent performance, high-priced gyro-sensors tend to be expensive and, as such, are not cost-effective when applied to mobile robots requiring cost competitiveness, e.g., robot vacuum cleaners. Thus, low-cost gyro-sensors are applied to such mobile robots. In order ensure satisfactory performance of a low-priced gyro-sensor even when it is applied to a robot vacuum cleaner, the low-priced gyro-sensor needs to be calibrated appropriately for achieving optimized performance.
First, gyro-sensors may be calibrated when manufactured. However, calibrating each of a considerable number of gyro-sensors may involve an increase in the manufacturing cost, which is not cost-effective. In addition, since the gyro-sensors and circuits characteristics may vary due to environmental factors changing with time, the accuracy of the gyro-sensors is likely to degrade after an extended use of period, which is generally called aging.
To address such a problem, in a conventional method of calibrating in real time a gyro-sensor in a mobile robot disclosed in Korean Patent Publication No. 10-2004-0062038, entitled “Method of Compensating for Offset of Robot Cleaner,” an orientation error of a robot cleaner is compensated for by correcting an offset value of a gyro-sensor, thus minimizing the orientation error of the robot cleaner regardless of variations in the offset of the gyro-sensor. However, an offset of the gyro-sensor can be compensated for only in a stop mode and a characteristic curve based on a gyro characteristic equation cannot be calibrated.